• Food Science and Preservation
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• v.19 no.3
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• pp.420-427
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• 2012

The objective of this research was to investigate the effect of immersion in Rhus verniciflua Stokes extract (RVSE) on the total reducing ability (TRA), protein oxidation and myoglobin oxidation of beef steak (Hanwoo longissimus muscle) stored with high oxygen-modified-atmosphere packaging (MAP) (HOMAP, 75% $O_2$+20% $CO_2$+5% $N_2$) and low oxygen-MAP (LOMAP, 0% $O_2$+20% $CO_2$+80% $N_2$) at $4^{\circ}C$ for nine days. RVSE induced TRA (p<0.05), metmyoglobin (MetMb) formation, and the CIE $H^{\circ}$ value but reduced the carbonyl content and R630-R580, as an index of the intensity of redness by oxymyoglobin, and the CIE $L^*$,$a^*$, and $C^*$ values. HOMAP maintained a lower TRA, MetMb concentration, and CIE $H^{\circ}$ value but had higher R630-R580 and CIE $L^*$, $a^*$, and $C^*$ values compared to LOMAP. Therefore, RVSE induced TRA and protein oxidation stability but reduced myoglobin stability in Hanwoo beef steak. In addition, the effects of HOMAP were opposite those of RVSE.

• Journal of Life Science
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• v.18 no.6
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• pp.839-844
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• 2008

A strain SH-517 which produce extracellular keratinase, was isolated from the soil of a poultry waste and a poultry factory. An isolate SH-517 was identified as Bacillus sp. based on its morphological and biochemical characteristics. The optimal culture conditions for the production of keratinase by Bacillus sp. SH-517 were investigated. The optimal medium composition for keratinase production was determined to be 2.0% chicken feather as carbon source, 0.5% beef extract as organic nitrogen source, 0.5% $KNO_3$ as inorganic nitrogen source and 0.06% KCl, 0.05% NaCl, 0.04% $KH_2PO_4$, 0.03% $K_2HPO_4$ as mineral source and 0.01% yeast extract as growth factor. The optimal temperature and pH of medium were shown $40^{\circ}C$ and 8.5 with shaking culture (180 rpm/min), respectively. The maximum keratinase production reached maximum of 125 units/ml/min after 42 hr of cultivation under the optimal culturing conditions.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.279-284
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• 1996

To develop a selective medium for the isolation and the detection of leuconostocs from the various samples including fermented vegetables, ten strains of leuconostocs and seven strains of lactobacilli were tested for their sensitivity to various antibiotics. The basal-medium containing 5 ${\mu}g/ml$ of novobiocin inhibited the growth of lactobacilli completely, but not that of leuconostocs. On the basis of this result, a new selective medium was developed and to be named NLS medium. This medium contains 1% Tryptone (Difco), 0.1% Yeast Extract (Difco), 2% sucrose, 0.1% Beef Extract (BBL), 0.5% sodium acetate, 0.2% ammonium sulfate, 0.01% magnesium sulfate, 0.2% dipotassium phosphate, 0.05% sorbic acid, 75 ppm sodium azide (Sigma), 0.1% (vol/vol) Tween 80, 30 ${\mu}g/ml$ of Vancomycin (Sigma), 5${\mu}g/ml$ of Novobiocin (Sigma), 0.5${\mu}g/ml$ of cysteine HCI, and 1.5% Agar (Difco). All of the eighty six isolates obtained from some foodstuffs were identified as members of the genus Leuconostoc. Comparative counts with the MRS, PES, LUSM, and NLS medium indicated that the recovery percent was lower than other selective media. Therefore, this result suggested that NLS medium was suitable for the isolation of leuconostocs, but not for counting or enumerating.

• The Korean Journal of Community Living Science
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• v.15 no.1
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• pp.105-113
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• 2004

This study investigated the synergy effects of hot water soluble extract from Eleutherococcus senticosus and dietarty carnitine on the lipid metabolism and antioxidant defense system of rats on hypercholesterol diets. Sprague-Dawley male rats were fed either a hypercholesterol diet with water or a hot water soluble extract from Eleutherococcus senticosus and dietarty carnitine. The experimental groups consisted of the control group (CO), the group supplied with hot water soluble extract from Eleutherococcus senticosus(ES), and the group supplied with hot water soluble extract from Eleutherococcus senticosus and dietarty carnitine(ESC). Eleutherococcus senticosus was extracted, made into 0.5% solution, and fed to the ES and ESC groups. A 3% carnitine diet was supplied to the ESC group. Hypercholesterol diets contained 18% beef tallow and 5% cholesterol. After 4 weeks of administering these diets, serum and liver were obtained and the level of serum lipid and the activities of GOT and GPT were measured. In addition, the level of liver lipid and TBARS and the activity of GSH-Px were measured. The results were as follows: 1) Weight gain and FER in the group supplied with hot water soluble extract from Eleutherococcus senticosus and dietarty carnitine(ESC) was low significantly(P<0.05). 2) In the groups supplied with hot water soluble extract from Eleutherococcus senticosus(ES) and the group supplied with hot water soluble extract from Eleutherocorcus senticosus and dietarty carnitine(ESC), total serum cholesterol levels were both significantly low (P<0.05,P.0.01). 3) Serum GOT activity was significantly low(P<0.05) in the group supplied with hot water soluble extract from Eleutherococcus senticosus(ES) and in the group supplied with hot water soluble extract from Eleutherococcus senticosus and dietary carnitine(ESC). There was no difference between serum GPT activity in the control group and the groups supplied with hot water soluble extract from Eleutherococcus senticosus or dietary carnitine. 4) Liver triglyceride was low (P.0.05) in the group supplied with hot water soluble extract from Eleutherococcus senticosus and dietarty carnitine(ESC). No difference was observed in other lipid composition, TBARS level, and GSH-px activity in liver between the control group and the experimental groups. In summary, the effects of hot water soluble extract from Eleutherococcus senticosus and dietarty carnitine on the lipid metabolism and antioxidant defense system (such as weight gain, FER, total serum cholesterol and liver triglyceride) were low when Eleutherococcus senticosus and dietarty carnitine were supplied simultaneously.

• Journal of Microbiology and Biotechnology
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• v.31 no.5
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• pp.717-725
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• 2021

This study aimed to optimize medium composition and culture conditions for enhancing the biomass of Lactobacillus plantarum 200655 using statistical methods. The one-factor-at-a-time (OFAT) method was used to screen the six carbon sources (glucose, sucrose, maltose, fructose, lactose, and galactose) and six nitrogen sources (peptone, tryptone, soytone, yeast extract, beef extract, and malt extract). Based on the OFAT results, six factors were selected for the Plackett-Burman design (PBD) to evaluate whether the variables had significant effects on the biomass. Maltose, yeast extract, and soytone were assessed as critical factors and therefore applied to response surface methodology (RSM). The optimal medium composition by RSM was composed of 31.29 g/l maltose, 30.27 g/l yeast extract, 39.43 g/l soytone, 5 g/l sodium acetate, 2 g/l K₂HPO₄, 1 g/l Tween 80, 0.1 g/l MgSO₄·7H₂O, and 0.05 g/l MnSO₄·H₂O, and the maximum biomass was predicted to be 3.951 g/l. Under the optimized medium, the biomass of L. plantarum 200655 was 3.845 g/l, which was similar to the predicted value and 1.58-fold higher than that of the unoptimized medium (2.429 g/l). Furthermore, the biomass increased to 4.505 g/l under optimized cultivation conditions. For lab-scale bioreactor validation, batch fermentation was conducted with a 5-L bioreactor containing 3.5 L of optimized medium. As a result, the highest yield of biomass (5.866 g/l) was obtained after 18 h of incubation at 30℃, pH 6.5, and 200 rpm. In conclusion, mass production by L. plantarum 200655 could be enhanced to obtain higher yields than that in MRS medium

• Korean Journal of Food Science and Technology
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• v.21 no.3
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• pp.375-378
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• 1989

The effect of lipid content and saline seasoning on the mutagenicity during the charcoal-broiling Process of beef, Pork and fish samples was examined by Ames test using Salmonella typhimurium TA98 and TA100 strains. Chloroform; methanol(1:1) extract of broiled samples showed a higher sensitive response toward TA98 strain than TA100 strain, indicating a frameshift mutation. The three samples of low lipid content demonstrated a slightly higher mutagenic activity, and the beef and pork samples treated with 20% saline solution showed a remarkable reduction in mutagenicity than the untreated samples.

• Food Science and Biotechnology
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• v.16 no.4
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• pp.572-575
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• 2007

The angiontensin converting enzyme (ACE) inhibitory peptides were separated from beef sarcoplasmic protein extract and their amino acid sequences were identified as GFHI, DFHINQ, FHG, and GLSDGEWQ. The 4 peptides were synthesized in a laboratory and the ACE inhibitory activities of pep tides was measured after 2 months of storage at $4^{\circ}C$ under different pH conditions (6.0, 6.5, 7.0, 7.5, and 8.0) and the exposure of different temperatures (70, 80, 90, and $100^{\circ}C$) for 20 min to evaluate industrial use. No significant difference was detected by pH and temperature abuse for 20 min during storage. When the synthetic peptides were digested by pepsin, trypsin, and chymotrypsin, the ACE inhibitory activity was not changed. These results indicated that the 4 synthetic peptides with ACE inhibitory activity were pH-stable, heat-stable, and resistant to proteinases in gastro-intestinal tracts. Therefore, those 4 peptides can be used as a source for functional food product with various applications.

• Journal of Practical Agriculture & Fisheries Research
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• v.25 no.4
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• pp.127-137
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• 2024

This study was conducted to investigate effect of corn flake and corn ground on nutrient digestibility and fermentation characteristics of rumen in Hanwoo. The animals used were three Hanwoo cows implanted with ruminal fistula. Corn were categorized in 2 groups based on the corn processing method: Ground and Flake. The rumen digestibility of dry matter, starch, nitrogen free extract and non fiber carbohydrates were increased in flake compared to ground from 3 to 24 hours of incubation(P<0.05). The pH of rumen was lower in the flaked treatment than ground treatment at 3 hours after incubation, but average pH was no significantly difference between treatments. The average acetic acid, propionic acid and butyric acid were significantly increased in the flaked treatments compared to the ground treatment (P<0.05). Thus, flake processing can improve the carbohydrate availability of corn in the rumen and increase feed value.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.747-754
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• 2000

DNA damages in post-mortem bovine muscle samples caused by gamma irradiation at doses of 1 to 10 kGy were determined by Comet assay. When the cell extract was prepared in a physical method and followed by neutral lysis and neutral electrophoresis, the optimal comet images could be obtained. DNA damages were evaluated from the mean tail length, the distributions of comet images in 4 groups divided by tail length and the relative damage index (RDI) values calculated from the distribution pattern. The mean tail length and RDI value were increased by increasing the irradiation dose, and the RDI value was found to be useful as an index for discriminating of irradiation and measuring the irradiated dose. Blind tests using Korean domestic (Hanwoo) and imported beef samples showed a higher RDI value for the latter. However, the value was lower than those of irradiated samples indicating that the cause of DNA damages in the imported beef samples might be not irradiation but low-temperature treatments. It was concluded from the results of this study that the irradiated beef and its irradiated dose could be detected and predicted by Comet assay.

• Korean journal of food and cookery science
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• v.30 no.4
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• pp.394-401
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• 2014

This study was carried out in order to investigate the effects of lotus leaf extracts on the quality characteristics of beef jerky, such as chemical composition, free amino acid, Hunter's color, physical properties, water activity, pH, TBARS value, VBN content, total bacterial count and sensory score. According to the results, there were no significant differences in moisture, protein, fat, ash, L-value, b-value, hardness, springiness, cohesiveness, gumminess, chewiness, water activity, pH, flavor, taste, texture, juiciness and overall acceptability. Total free amino acid content was highest in T0 and, lowest in T3 (p<0.05). The a-value was highest in T3 (p<0.05). The TBARS value and total bacterial count of T2 and T3 were significantly lower than those of T0 and T1 (p<0.05). The VBN content was lowest in T3 (p<0.05) and the sensory color was highest in T3 (p<0.05).